FX: stereo vs.mono

[dmitch]

Is there any info (documentation, previous threads, etc.) which discusses the issue of stereo vs. mono for stomps and rack FX? For example:

-- Most rack FX units appear to be stereo. True?
-- All stomp boxes appear to be mono. True?
-- What happens when you put a stereo rack effect in a mono signal path (i.e. a stomp board)? Does the mono input go to both stereo inputs of the effect, and are the stereo effect outputs summed?
-- What happens when you put a mono effect in a stereo signal path (e.g. a stomp on a stereo output bus)? Do you get essentially two copies of the effect, one for each channel? Or do you lose your stereo separation by combining both channels into one input for a single effect?

Thanks.

[garfy]

Hi dmitch

I can't see anything that goes into any depth in the manual but I've done a few experiments.

-- Most rack FX units appear to be stereo. True?
-- All stomp boxes appear to be mono. True?

I find this to be true as far as I've gone.

What happens when you put a stereo rack effect in a mono signal path (i.e. a stomp board)? Does the mono input go to both stereo inputs of the effect, and are the stereo effect outputs summed?

This depends on where you put it and what happens afterwards. For example, the Autopan rack effect is the easiest to track what's going on, coz it's got lights on it

On a mono input to a single amp/cab the panning has no L/R effect, which is as theory dictates.
When you have a 2 amp/cab set up, if you put it before the split then it stays mono, again as per the theory and your conclusion of summing.
If you have a 2 amp/cab set up, put the Autopanner AFTER the split before the amps AND pan the cabs to the L/R then you get the stereo pan. So, the rack effects change dependent on where they are in the signal flow.

What happens when you put a mono effect in a stereo signal path (e.g. a stomp on a stereo output bus)? Do you get essentially two copies of the effect, one for each channel? Or do you lose your stereo separation by combining both channels into one input for a single effect?

Using the set up above with the stereo, auto panned amp/cabs, if I inserted a compressor stomp into the stereo master output, the autopan carried on doing its left to right thing and was compressed by the pedal. So, again, the stomps change dependent on where they are in the signal flow.

Whether this carries for all stomps and racks is a nice little project for someone else to find out. In conclusion...

Most rack FX units appear to be stereo. True?
-- All stomp boxes appear to be mono. True?

...it depends.

Hope that helps in some way.

[dmitch]

I can't see anything that goes into any depth in the manual but I've done a few experiments.

Excellent info. Thanks!